There is a key element in the production of polymer notes that makes it fairly easy for anyone with a note in hand to determine if some ink from intaglio or letterpress or even lithographic printing was removed post production.
This is because the final element that gets "printed" on the polymer sheet is the varnish. The varnish provides a unique sheen to the surface of the ink which when removed removes that sheen. Pick up any note from circulation which has excessive folds and creases and you will be able to notice this difference where the varnish has worn off. Just view the note at a low angle.
For the note that was listed on the e-bay there is an additional thing that tells that this is a suspect note. The lithographic printing element bleeds into the area printed with intaglio. There is clear evidence on this note even without substantial magnification that this underlying lithographic printing has been removed.
Someone suggested in one of the posts that if the intaglio embossing is on the note but there is no ink on the note than it is a tell tale sign that the ink has been removed.
In my humble opinion this is erroneous. It is a known fact that when the cells in the engraved plate are starved of ink then it will leave an embossing but not leave any ink. One very prominent polymer bank note author/collector/vendor used to have error notes on their website and had shown many fine examples of such an error because of ink starvation.
This can be seen with the intaglio printing of the Queen's portrait on the $20 bill. I have done extensive studies of notes from new bundles where it is easy to spot (although not common) such missing intaglio areas caused by cells starved of ink. When they occur they even repeat with some known frequency in the exact same spots in a manner that can be explained in terms of the the printing process (Please refer to an article on this in the June 2016 issue of CPMS Journal).
Here is an image (click thumbnail for higher magnification) where intaglio is missing because of ink starvation in the cell.
You will notice that in this example the underlying ink is completely intact. What is not noticeable in a scan but is easily seen when viewing the note at an angle is that the varnish is also intact. You will also notice in the higher magnification the outline of the cells have ink but the centre of the cell is missing ink.
The bottom line is that post-production either the ink is removed by using chemicals or by abrasion. In either case the overlying varnish will have to be noticeable impacted (particular for such a larger area of missing ink).
The likelihood of the underlying ink and/or the surface being affected is also very high particularly if abrasion is used.
If anyone can create this condition on a polymer banknote without affecting the varnish and without affecting the underlying ink and still keeping the note in a UNC condition I would request them to put the note up for sale on the trading post. For a $5 denomination polymer note I am willing to pay a premium.
Although my reply talks to some of the technical aspects, I somehow gather that the original post has raised a very important aspect about who they believe has put up the note for sale and the provenance of that note. CPMF is a well regarded forum and if it is true that long standing members of CPMF are closely associated with such ebay listings then it only makes sense for them to address point 5 in the original post. Otherwise IMHO CPMF loses credibility.
